This application claims the benefit of German patent application DEP10045919.6, filed Sep. 16, 2000, herein incorporated by reference.
The present invention relates generally to a device for controlling a creel of a textile machine and, more particularly, to a device for controlling a creel which is pivotable to a limited degree and can be loaded with a defined torque by a torque generator which is controlled by a drive mechanism.
A device of the described type for controlling a creel of a textile machine is described in German Patent Publication DE 198 17 363 A1, for example.
With this known device, a bobbin held in a creel is driven by a roller by means of friction. It is intended in this device to provide an exactly predetermined bobbin contact pressure between the driving roller and the bobbin, which can be controlled in order to be able, for example, to set a defined slippage between the bobbin and the roller.
Therefore the creel is supported by means of a pivot shaft to be pivotable to a limited degree thereabout, with a connecting disk being fixedly connected with the pivot shaft against relative rotation.
In addition, the connecting disk is connected by means of helical springs with a gear wheel such that rotation of the gear wheel by means of a drive motor, in particular a step motor, generates a torque acting on the connecting disk and therefore on the pivot shaft. In order to be able to introduce a sufficiently large torque into the pivot shaft, a total of six helical springs, which are arranged tangentially in respect to the pivot shaft, are provided between the gear wheel and the connecting disk.
In view of the above mentioned state of the art, an object of the present invention is to provide a device for the defined control of a creel, which is particularly effective and at the same time cost-effective and simple in construction.
In accordance with the present invention, this object is addressed in a creel of the aforedescribed type by providing a reduction gear arrangement for connecting the torque generator with the creel.
By the employment of a reduction gear arrangement, it is possible to utilize a torque generator which is relatively low-powered and simply. The high torque required for the defined control of the creel is nevertheless assuredly provided.
In a preferred embodiment, the torque generator advantageously has a flat coil spring.
By using a flat coil spring it is possible to achieve a very simple, cost-effective construction of the entire device. For this purpose, one end of the flat coil spring is fastened on a first element of the torque generator, which is displaced by a drive element. The other end of the flat coil spring is connected with a second element, which is coupled with a gear. The flat coil spring generates a defined force by the rotation of the first element in respect to the second element, and this force is converted into torque. Advantageously, this defined force can be adjusted within wide margins since the flat coil spring can be rotated over a large angle because of its type of construction.
In an advantageous embodiment of the invention, the gear arrangement is embodied as a ribbon gear. A generation of the torque free of play at the pivot shaft can be achieved with the aid of a ribbon gear. This is advantageous in promoting the exact control of the creel, and therefore in promoting an exactly set bobbin contact pressure.
In an alternative embodiment, the torque generator can also be directly connected with a driveshaft of the drive element, which results in a direct control of the torque generator by means of the drive element. The number of required components is reduced by this arrangement.
It is further preferred in an advantageous embodiment of the present invention that another gear arrangement is arranged between the drive element and the torque generator. Thus, the torque generator is arranged between two gears, or between two gear arrangements, which results in an extremely flexible design of the device in accordance with the invention. For example, a low-powered and cost-effective step motor can be used as the drive motor.
Further characteristics and advantages of the present invention will be described and understood from the following description together with the accompanying drawings.